Extensible chair



March 13, 1934. A. J. MAY

EXTENSIBLE CHAIR Filed Sept; 16, 1929 7 Sheets-Sheet 1 March 13, 1934,

A. J. MAY I EXTENSIBLE CHAIR 7 Sheets-Sheet 2 Filed Sept. 16, 1929INVENTOR m wk March 13, 1934. A. J. MAY

EXTENSIBLE CHAIR Filed Sept. 16, 1929 'T Sheets-Sheet 3 INVENTOR IQZWLJjZgy %z' ATTo EY March 13, 1934. A J MAY 1,950,619

EXTENSIBLE CHAIR Filed Sept. 16 1929 7 Sheets-Sheet 4 aaaon INVENTORMarch 13, 1934. A. J. MAY

EXTENSIBLE CHAIR Filed Sept. 16, 1929 7 Sheets-Sheet 5 A. J. MAY

EXTENSIBLE CHAIR March 13, 1934.

Filed Sept. 16, 1929 7 Sheets-Sheet 6 m a W 5 w w%, m a a w w H Y 9 i 6Q :2: i a w 1 w llvlEmw g 5 a March 13, 1934. A. J. MAY 1,950,619

EXTENSIBLE CHA IR Filed Sept. 16 1929 7 Sheets-Sheet 7 INVENTOR Patentedar. l3, 1934 STATES Dental Manufacturing (30.,

Inc, Rochester,

N. Y., a corporation of Delaware Application September l6, i929, SerialNo. 392.8%

18 Claims. (Cl. 15%25) The present invention relates to extensiblechairs and has for one object to provide an improved chair of this classhaving one or more columns or sections to be raised and lowered, theinvention being particularly, adaptable for use on dental, surgical andbarber chairs.

A further object of the invention is to provide improved means forcontrolling the operation of electrically driven lifts for chair seatsor supports, and more particularly, means by which to control theoperations of a reversible electric motor for operating the lift wherebythe up and down movements of one or more parts are utilized togetherwith manual control means for starting, stopping, and reversing themotor when desired.

A further object of the invention is to provide an'extensible motoractuated chair. lifting mechanism having improved electrical controldevices for rendering the motor ineffective when the, parts have reacheddifierent positions of adjustment, said devices being coordinated towerfeet control of the movements of the extensible parts in a manner tosimplify the work of the operator.

A further object of the invention is to pro-= vide in combination with amotor operated lift, such. for example, as an electrically driven chaircolumn or section, an improved switch for controlling the motor circuit,arranged for operation manually as well as automatically by the up anddown movements of the column whereby to avoid the expense of applyingseparate limit and reversing switches for controlling the operation ofthe motor as heretofore employed in extensible chairs or lifts of thepresent type.

A further object of the invention is to pro vide in combination with amovable chair section and a reversible electric motor for operat-= ingthe same, a unitary switch for reversing the motor circuit having spacedoperating elements so arranged as to permit of manual control of theswitch from one or more points and also having operating meansassociated with a movable, part of the chair for automatic operationwhereby to break the circuit when said part reaches differentpredetermined positions.

A further object of the invention is to provide an improved switch forreversible electric motors designed both for manual and auto matlcoperation, the switch being of simple con struction, comparativelyinexpensive to manufacture and eificient in service.

A further object of the invention is to 'provide an improved electricswitch of the mercury tube type designed particularly for use as acombined reversing and limit switch for operation by difierent controldevices but independently operable by a single control device.

To these and other ends the invention resides in certain improvementsand combinations of parts, all as will be hereinafter more fullydescribed, the novel features being pointed out in the claims at the endof the specification.

In the drawings:

Fig. l is a side elevation of a chair embodying the invention;

Fig 2 is a part sectional plan of the base of the chair showing themotor and seat raising columns;

Fig. 3 is a fragmentary sectional elevation partially illustrating theoperating means for the seat raising columns;

Fig. i is a sectional elevation of the switch it taken substantially online la la of Fig. 8; Fig. 5 is a sectional elevation takensubstantially on line 5a-5a of Fig. 8 with the switch in one of itscircuit closing positions;

Fig. 5 is a similar section of the switch in so circuit breakingposition;

Fig. '5 is a view similar to Fig. 4 with the switch in one of-itscircuit closing positions;

Fig. 8 is a fragmentary sectional plan through the base of the chairshowing the switch and 86 operating pedals therefor with parts of theswitch in section;

Fig. 9 is a sectional plan or" one of cury tube holders;

10 is a sectional elevation taken substan= tially on line loa10a of Fig.8;

Fig. 11 is a fragmentary sectional elevation taken on line lla-lla ofFig. 8 showing the operating means for the switch designed to beactuated by one of the chair columns;

Fig. 12 is a sectional elevation taken on line' max-12a of Fig. 8;

Fig. 13 is a view similar to Fig. 11 with the switch in a positioncorresponding to that shown in Fig. '3 to which it is moved bydepressing one i the pedals;

Fig. la is a view in elevation showing one of the mercury tube operatingsegments;

Fig. 15 is a part sectional elevation showing the segment coupled withone of the operating elements therefor arranged to be actuated by thevertical movement of the chair column, and

Fig. 16 is a diagrammatic view illustrating the motor circuitarrangement.

the mer- Similar reference numerals throughout the several viewsindicate the same parts.

In the present invention I have provided a chair having extensiblesections with a reversible electric motor for operating any suitablelifting mechanism for one or more sections. Heretofore it has beencustomary to provide both a reversing switch and a limit switch ondifferent parts of the chair to effect reversal of the motor andbreaking of the circuit when the sections approach the limits of theirmovements, in cases where the operator fails to release the pedal. Inthe present invention I provide a combined limit and reversing switch tobe manually actuated under normal operating conditions and arranged forautomatic operation preferably by a moving part of the lifting mechanismor one of the sections, in the case of an emergency.

The switch embodies a new and novel construction in which'twocooperating mercury tube switch elements are employed for controllingthe motor circuits, together with improved operating means for saidelements which can be conveniently controlled from different sides ofthe chair base.

By combining the limit or safety switch'with the operating or reversingswitch the number of parts used are considerably reduced and the cost ofproduction lowered while the efficiency of the circuit control mechanismis increased over prior arrangements embodying separate switches.

Referring to the drawings, 10 represents the base of the chair withinwhich is disposed inner and outer columns or sections 11 and 12respectively and with which is associated a reversible electric motor 13for operating the sections to raise the chair seat frame 14. Theoperating means interposed between the motor and extensible sections maybe of any preferred type suitable'for the purpose. The motor drivenoperating means shown in the drawings by way of example is the same asthat disclosed in Patent No. 1,700,741, issued February 5, 1929. Thismechanism which will be briefly described comprises a worm shaft 15suitably connected with the motor shaft 15a. A worm 16 on the worm shaftmeshes with a worm wheel 1'7 on a shaft 18 carrying a pinion 18a fordriving a gear 19 which serves to drive a similar gear 190. on a shaft20. The shaft 20 has its outer end journaled in the gear casing 21 andits inner end journaled in a standard 22 projecting from the bottom 23of the base into the column 11. The drive shaft 20 has a sprocket 24thereon for driving a chain 25 extending over a pulley 26 journaled inthe top of the standard, the chain extending under a pulley (not shown)journaled on the bottom of the outer column 12, from which pulley thechain extends upwardly out side of the column 12 to a point where it isanchored upon the upper end of the base 10. The opposite end of thechain is carried under the sprocket and is extended upwardly a shortdistance and connected with a verticallydisposed rod (not shown) havingits upper end yieldably connected with the top of the inner column 11all as clearly shown in the above mentioned patent. The sprocket chainserves to raise the outer column 12 and the inner column is raised bythe outer column by means of a pair of chains or flexible elements 2'1extending over pulleys 28 Journaled on the upper end of the outercolumn. The chains have their lower ends connected with lugs 29 and 30carried respectively by the inner support being removably secured to thebase preferably by a suitable number of screws or bolts (not shown). Ata point opposite the support the-base is provided with a verticallydisposed wall portion 32 for receiving certainparts of the switchmechanism described hereinafter.

The movable elements of the switch preferably comprise two mercuryholding tubes 33 and 33a constructed of glass or other suitable materialand having the required amount of mercury, indicated at 34, therein. Thetubes are similarly constructed, but are reversed so that in either ofthe tilted positions shown in Figs. 5 and 7, three of the contacts ofone tube and two of the other will project within the mercury,regardless of which circuit closing position the tubes may occupy. Thecontacts of the left hand tube shown in Fig. 4, are indicated by thecharacters 35 to 38 inclusive and the corresponding contacts of tube 33aare indicated by the characters 35a to 38a inclusive. These contacts areelectrically connected with the reversible motor as illustrated in thewiring diagram shown in Fig. 16 and fully explained hereinafter.

The tubes are swung from the normal inoperative position shown in Fig. 6to either circuit closing position by a pair of segments or pivotedelements 39 and 40 which have intermeshing teeth as shown, the segment40 being arranged to operate segment 39 when swung in eitherdirectiorrfrom the normal position shown in Fig. 6.

The tubesare each carried by an oscillatory support or rocker best shownin Figs. 9 and 10, each comprising a plate-like arm 41 having struckupwardly therefrom a central yoke-like portional 41a on the inner end ofwhich is fixed a bearing 42 and on the outer end a spindle 43. Thebearing 42 is held in a sleeve-like portion of a bell-crank lever 44journaled in the wall 32 of the pedestal base and the spindle 43 isjournaled in a sleeve 45 carried by the front wall of the switch support31, Fig. 10. A screw 46 threaded into the end of the spindle 43 engagesa washer 47 seated on the wall 31 to limit the inward movement of theoscillatory tube support. The arm 41 carries on its inner face a holderfor the mercury tube comprising a plate 48 having a plurality ofspring-like fingers 49 partially surrounding the tube and permitting itto be removed from the holder when desired.

The segments 39 and 40 are seated on the outer faces of the arms 41 andare-held against outward movement by the sleeve bearings 45 in which thespindles 43 are iournaled. The segments are each coupled with one of thearms for movement relative thereto and are arranged under normalconditions of operation of the chair columns to move with the arms uponoscillation of the same. The segments serve to operate the arms sincethe latter have pins 50 projecting through slots 51 in the segments inwhich thepins are centrally held each by the opposite ends of a spring52 coiled about the sleeve bearing 45, Fig. 10. The ends of the springare crossed, Fig. 15, and extend on opposite sides of a pin 53 on thesegment and into engagement with the pin 50 on the arm, so that undernormal operation the spring constitutes assume -tion of the segment 46relative to the arm 41 as shown in Fig. 15 is that which results whenthe operator continues to hold down the pedal as the chair column 12reaches one of its extreme positions of movement. in this case a deviceoperatedby said column explained hereinafter will rock the beil-cranklevers 44, the bearings 42 and arms it against the resistance of thesprings 52 so that the arms and tubes thereon are brought to thehorizontal circuit breaking position shown in Figs. 6 and 15. As soonthereafter as the pedal is released the segments 39 and 40 will beautomatically returned to normal position, partially by the por: tion ofthe spring 52 acting on the pin 53 of the segment but more positively bymeans hereinafter described.

Means is provided for preventing a quick throw of the mercury tubes fromcircuit closing to circuit opening position in order to preventsplashing or undue shifting of the mercury within the tubes whereby toavoid accidental closing of the circuit should the operator suddenlyrelease the pedal. In carrying out this idea the preferred meansemployed is in the form of a dashpot although other suitable means maybe substituted therefor if desired. The dashpot, which may be either ofpneumatic or hydraulic type, comprises a closed cylinder 54 having apiston 54a therein actuated by a stem 55 pivotally connected with an arm56 on the segment 40. The opposite segment 39' carries an arm 5'7 whichis pivotally connected with the cylinder 54. In the normal position ofthe dashpot as shown in Fig. 6, the piston will occupy a positionsubstantially midway between the ends of the cylinder. However when theswitch is operated to the extreme positions shown in Figs. 5 and 7 andthe pedal released, the piston will be moved in a direction to affordthe desired cushioning effect and the mercury tubes will be slowlyreturned to the normal position shown in Fig. 4 without unduly agitatingthe mercury.

Operation of the segments 39 and to may be effected by any suitablemeans for swinging them about their axes to cause shifting of themercury tubes for the purpose of opening and closing one or morecircuits by a change in the position of the mercury within the tubes orby othere means responsive to the action of gravity which may besuitable for'the purpose, either in the form of a liquid or a solid.

The present operating means shown by way of example, comprises aplurality of foot peda-is on the base of the chair, each of which isoperable to shift the mercury tubes from normal to a circuit closingposition. With the present arrangement of pedals, best shown in Figs. 28, the operator when standing at. the basis the chair can operate theswitch to efiect up and of the gear 64 are in mesh with those oi two'bracket 31. 'member 74 and is fixed on an extended porgear segments 66and 67 which are fixed on pivot members 68 journaled in bearings 69 ofthe bracket 31, the segments being held inposition by screws 70, Figs. 5and 10. On the other ends of the pivot members 68, pedals 1'1 and 72 arefixed which extend in opposite directions and somewhat beyond the pedals58 and 59 for convenient control by the operator when he is standing atthe sides of the chair,

in which case pedals 58 and 71 will be depressed in raising and loweringthe chair column if the operator is standing at one side of the chairand if he is at the opposite side, pedals59 and 72 will be depressed forthe same purpose. On the other hand if, the operator is standing at theback of the chair pedals 58 and 59 will be depressed to effect theclosing of the switch for the up and down movements of the chairsections.

Operation of both mercury tubes in opposite directions is effectedthrough the rocking of segment 67, the teeth of which are in mesh withthose on the lower portion of segment 40. The oscillation of segment 67may be effected by depressing pedal 71 which is directly connected withsaid segment or by depressing pedal 72 which is directly connected withsegment 66, the latter being operatively connected with the gear orsegment 64 which is i noperativeengagement with segment 67.

Return of the pedals and the mercury tubes to normal circuit breakingposition from either circuit closing position is effected preferably bya spring 73 coiled about the bearing portion 63 of the pivot member 61for operating the gear 64, Fig. 12. The ends of the spring are crossedand normally engage. opposite sides of an inwardly extending member 74on the wall of the A similar member '75 underlies the tion 76 of thegear 6e. Upon rocking the gear to the right or left of the positionshown in Fig. i, the projecting member thereon will either move one orthe other end portions of the spring in a direction to increase thetension of the spring and upon release of any one of the pedals thespring will return the gear 64 to central position, thus causing thereturn or" the segments 39 and 40 and the tubes thereon to the normalcircuit breaking position shown in Fig. 4, during which return movementthe dashpot '54 wili check the speed of the parts and prevent undueagitation of the mercury within the tubes.

The bracket 31 and all parts thereon may be inserted upon and withdrawnfrom the chair base in a unit since the members 42 are arranged to slidewithin the sleeve-like portions of the bell-crank levers 44.- by reasonof the fact that said members are slotted at 42a to receive the pins 43acarried by said levers.

Means by which the switch is automatically moved to circuit breakingposition when the chair column or section 12 approaches its 1i m its ofmovement includes the bell-crank levers and a yoke "7 connected with thearms of the levers by means pins 78 disposed in slots 79 formed in saidarms, the slots permitting the arms to swing through the required arcsupon operating the pedals to move the tubes to the different circuitclosing positions. The yol-ze carries an upstanding rod 80 on the upperend of which is disposed a head 81, while spring 82 is secured upon therod adjacent the head for a purpose which will presently appear. The

column 12 has a lug 83 thereon which is provided .with an openingthrough which the rod projects. In cases where the operator may notthink to release the pedal before the column reaches the limits of itsup and down movements, the lug, on the upward stroke of the column willengage the spring 82 and cause the rod to lift the yoke whereby to swingthe tube holding arms 41 to normal circuit breaking position. The sameresult is afforded on the downward movement of the column by reason ofthe fact that the lug will engage and shift the yoke to swing the tubeholding arms from the position shown in Fig. 5 to that shown in Fig. 11,assuming of course that the operator has failed to release the pedal.

The mercury tubes are so designed that either can be used as a switch,independently of the other, for controlling one or more electriccircuits. By mounting one of the tubes on a pivoted member, such as thesegment 40, the latter can be operated by the gear segment 67 and pedal71 to adjust it either to a horizontal circuit breaking position or totwo diiferent circuit closing positions, in one of which the contacts37a and 3811 will engage the mercury as shown in Fig. 5 and in the otherof which the contacts 35a and 37a will project into the mercury with thetube in the position shown in Fig. '7, the contact 3611 being retainedor omitted as may be required. Thus each tube constitutes a switch byitself in which the contact 37a in tube 33a would be common to bothcircuits.

The D. C. motor shown in Fig. 16 is indicated generally by the referencecharacter 13a and embodies the usual armature 84 and series and shuntcoils 85 and 86 respectively. In the circuit closing position of themercury tubes shown the contacts engaged by the mercury are indicated bythe reference characters 35, 36, 37, 37a and 38a, and it is thesecontacts which are included in the circuit. The line wire 87 isconnected with the series coil 85 which is connected with contact 38a bywires 88 and 89. Contact 37a projecting within the mercury is connectedwith the armature by a wire 90 and leading from the armature is a wire91 which. is connected with contact 37 in tube 33 which corresponds tocontact 37a in the tube 33a. Contact 35'projects into the mercury oftube 33 and is thus connected with contact 37, contact 35 beingconnected with wire 92 which leads to line wire 93. The shunt coil 86has one end connected to wire 88 and the other end is connected withwires 94 and 95, the latter of which extends to contact 36 projectinginto the mercury of tube 33 whereby to complete the shunt circuit.

Reversal of the motor circuit will be effected by shifting the tubes tothe position shown in Fig. 7, in which case contacts 3'7 and 38 willengage the mercury within tube 33 and contacts 35a, 36a and 37a. willproject into the mercury within the tube 330 to complete the circuitthrough certain wires common to both circuits and additional wires 88a,93a and 94a connected respectively with wires 88, 93 and 94, it beingunderstood that on reversing of the circuit contacts 35, 36 and 38a willno longer project within the mercury. It should be remembered, however,that in either closing position of the switch, contacts 37 and 37a arepartially im-- mersed within the mercury and are therefore common toboth circuits. In the normal position of the switch none of the contactswill engage the mercury other than 37 and 37a and the circuit can beclosed only by shifting the mercury tubes from normal positionsimultaneously to one of the two circuit closing positions shown.

In order to prevent the possibility of burning out the contacts througharcking when making and breaking the circuit, a suitable condenser 95 isinterposed in the circuit which will operate, through concentration ofthe current, to protect the contacts when the mercury flows to or fromengagement therewith on shifting the tubes to and from normal position.

While a D. C. motor is shown for operating the chair raising mechanisman A. C. motor may be substituted therefor if desired, in which case thewires leading to contacts 36 and 36a will be omitted since the shuntcoil will not be used.

In the raising and lowering operations of the chair columns or sectionsthe operator, if standing at the back of the chair, will depress one ofthe pedals 58 or 59 depending on whether or not the chair is to be movedup or down. Assuming that it is required to depress pedal 59 in order tocause the column to move upwardly 1 then the mercury holding tubes willbe moved to the circuit closing position shown in Fig. 'l, 4 and themotor will begin to operate to lift the column. As long as the operatorholds the pedal 59 depressed the circuit will remain closed unless thecolumns are moved to their upper limits. In this event the member 83 onthe outer column 12 will engage the spring 82 on the rod 80 and causethe latter to lift the yoke 77 sufficiently to return the tubes tohorizontal 11 circuit breaking position, regardless of the fact that thepedal may still be held in lowered position. It will be seen thereforethat since the segments 39 and 40 are free to rotate on their pivots 43,and since the tubes are fixed with 1 respect to said pivots theresistance of the springs 52 must be overcome to permit relativemovement between the segments and tubes or movement from the normalposition of said parts as shown in Fig. 5 to the position shown in Fig.6.

If instead of depressing pedal 59, the opposite pedal 58 be depressed tolower the chair columns, the lug 83 on column 12 will engage the yoke 77to operate the switch, provided the pedal is not Fig. 6 while thesegments 39 and 40 will remain inclined upwardly as shown. The lug 83 onthe descending column in this case constitutes the operating means forthe switch since when it reaches the yoke 77 it begins to move itdownwardly to cause the bell-crank levers 44 to shift the segments 39and 40 and the tubes thereon from the position shown in Fig. 5 to thatshown in Fig. 6, the segments remaining in the inclined position shownfor the reason that the pedal is still held in lowered position bytheoperator. However, as soon as the operator releases the pedal thesegments will be automatically returned to normal position by the actionof the spring 73 which returns the gear 64 to normal position therebyoperating gear 1 segment 67 which in turn operates segment 40 with whichsegment 39 is operatively connected. It will be understood that when theyoke '17 12 to return the mercury tubes to circuit breaking'po'sltion,said yoke will be in an elevated position above that shown in Fig. 11,the lug being shown in its lowermostposition in this figure. Theposition of the-yoke shown in Fig. 13 is that to which it is moved bydepressing either pedal 59 or 71 to shift the tubes to the circuitclosing position shown in Figs. 7 and- 13, in which position the motorwill operate to lift the chaircolumns. If it is desired to lower thechair columns either pedal 58 or '72 will be depressed. If the operatoris standing at the back of the chairhe can effect raising and loweringof the columns by respectively depressing pedals 59 and 58 and if he ispositioned at the right side of the chair as viewed in Fig. 8,depression of pedals 59 and 72 respectively will cause the motorfltoraise and lower the chair. Likewise if the operator is at the left ofthe chair depression of pedal 71 will result in raising of the columnsand depression of pedal 58 will result in lowering of the same. It isevident therefore that pedals 58 and 71 constitute one set for eifectingthe up and down movements of the chair sections and pedals 59 and 72constitute another set, and that pedals 58 and 59 constitute stillanother set, all for controlling the motor circuits and therefore themovements of the columns and the chair seat to be raised and loweredthereby.

I claim as'my invention:

1, The combination with a chair base and a reciprocally/mounted sectionthereon, mechanism for raising and lowering said section including anelectric motor, of a mercury controlled switch including mercury holdingmeans for controlling the motor circuit, means for manually moving saidmercury holding means to close the circuit and means controlled by thesection for moving the mercury holding means to circuit breakingposition when the section is moved to a. predetermined position.

2. The combination with a chair including a reciprocally mounted sectionand electrically driven power means omrativelyassociated with saidsection arranged to operate in reverse di rections, of a switchadjustable to reverse the circuit of said power means, manually operablemeans for reversing said switch and means controlled by said section foroperating the switch to break the circuit when the section is moved to apredetermined position.

3. The combination with a chair base having a reciprocally mountedsection thereon and a reversible electric motor for operating said section, of a fluid contact switch having circuit connections with saidmotor, oscillatory supporting means for said switch means for operatingsaid switch supporting'means to move the switch to different circuitclosing positions whereby to effect reversal of the motor, and meansunder the controlof said section arranged in difierent predeterminedpositions thereof to efiect movement or the oscillatory supportingmeansto move the switch to circuit breaking position whereby to discontinueoperation of the motor. I

i. The combination with a chair base having a vertically movable sectionthereon and a re versible electric motor for operating said section, oi"adjustable switch means having circuit connections with said motor,means for manually adjusting said switch means to effect reversaloi themotor circuit device operatively connected with said adjustable switchmeans ineluding a member disposed adjacent one side of the movablesection, and a part movable with the section arranged. in difl'erentpredetermined positions of the latter to operate said member whereby tobreak the motor circuit.

5. The combination with a chair base including a reciprocally mountedsection and electrically driven power means operatively associated withsaid section for reciprocating the same, of circuit control meanselectrically connected with said power means comprising a pair ofadjustable switch units normally in circuit breaking position, manuallyoperable means for simultaneously moving said units to either of twocircuit closing positions whereby to start operation of said power meansoperating means for moving said units to circuit breaking position, andmeans on said section arranged when the section is moved to differentpredetermined positions to shift said operating means whereby to movesaid units to circuit breaking position.

6. The combination with a chair base and a reciprocally mounted sectionthereon, a reversible electric motor operatively connected with saidsection, of a pair of relatively movable mercury tube switch units eachincluded in the motor circuit, operating means for simultaneously movingsaid units one relative to another and each in either of two directionsduring relative movement to close the motor circuit and means forreturning the units to normal circuit breaking position when theoperating means is released.

7. The combination with a chair base and a reciprocally mounted sectionthereon, a reversible electric motor operatively connected with saidsection, of a pair of mercury tube switch units each included in themotor circuit, manually operable means for simultaneously moving saidunits in either of two directions to close the motor circuit, springmeans for returning the units to normal circuit breaking position whenthe operating means is released, means responsive to the movement of thesection when the latter is in a predetermined position operating to movesaid units to circuit breaking position when the manually operable meansis held against release and means for retarding the movement of theunits to normal position by the spring means.

8. The combination with a chair base and a reciprocally mounted sectionthereon, a reversible electric motor operatively connected with saidsection, of a pair of mercury tube switch units included in the motorcircuit, manually controlled. operating means for simultaneously movingsaid units in either of two directions to close the motor circuit andmeans-for moving said switch units to circuit breaking position uponmovement of the chair section to different predetermined positions, saidmeans being operated by the section when it is moved to either of saidpositions.

a. The combination with a chair base and a reciprocally mounted sectionthereon, a revers ible electric motor o.eratively connected with saidsection for moving it upon the base be tween predetermined limits, of'means for reversing the motor circuit including a tiltable tube havinggravity responsive means therein for making and breaking the circuit,manually operable means for said tube and additional op:- erating meansassociated with said manually operable means for moving the tube tocircuit breaking position, said additional operating means beingoperated by the section upon reach" ing said predetermined limits.

its

10. The combination with a chair base and a reciprocally mounted chairsection thereon, a reversible electric motor operatively connected withsaid section for moving it upon the base between predeterminedpositions,of a pair of cooperating switch units included in the motor circuit andarranged to swing upon the base to and from different circuit closingpositions, means for manually operating said units to said differentcircuit closing positions, an actuating device for moving said switchunits to circuit breaking position, and spaced operating members uponsaid section arranged to operate the actuating device to break thecircuit when the section is moved to said predetermined positions.

11. The combination with a chair base and-a reciprocally mounted sectionthereon, mechanism for raising and lowering said section including anelectric motor, a mercury tube switch for. contiolling the motor circuitcomprising relatively movable mercury holding containers with contactstherein for cooperation with the mercury in relatively diiferentpositions of the containers whereby the circuit is closed with thecontainers in either of said positions, means for manually operating theswitch to move the containers to either of said circuit closingpositions, and means actuated by the section at either o1v its limits ofmovement for moving the containers from either circuit closing positionto circuit breaking position.

12. The combination of a chair base and a reciprocally mounted chairsection thereon, a reversible electric motor operatively connected withthe section for moving it upon the base between predetermined positions,of a pair of cooperating switch units included in the motor circuit andmounted for movement upon the base to and from circuit closing position,actuating elements for the units connected for operation one by another,the latter having an operating part therfor, manually operable meansconnected with said part to effect movement of said units to circuitclosing position, and means under the control of said section arrangedin diflerent predetermined positions thereof to move saidunits tocircuit breaking position.

13. The combination with a chair base having a reciprocally mountedsection thereon and a reversible electric motor for operating saidsection, of a switch comprising spaced oscillatory supports havingthereon cooperating switch units for reversing the motor circuit, meansfor manually operating said supports to effect reversal of the circuit,and additional operating means for the supports responsive to the up anddown movements of the section whereby to break the circuit in diiferentpredetermined positions of the section.

14. The combination with a chair base having a reciprocally mountedsection thereon and a reversible electric motor for operating saidsection, 01' a switch comprising spaced oscillatory supports havingthereon cooperating switch units for reversing the motor circuit, meansfor manually operating said supports to effect reversal of the circuit,and additional operating means for the supports including a link betweenthe supports having an actuating part responsive to the movement of saidsection in a predetermined position thereof whereby to break thecircuit.

15. The combination with a chair base having a reciprocally mountedsection thereon and a reversible electric motor for operating saidsection, of a-switch comprising cooperating units for reversing themotor circuit, oscillatory supports for said units, a pedal operativelyconnected with said supports for moving the switch units to effectreversal of the circuit, additional operating parts connected with saidsupports,

and a connection between said parts provided with an operating elementarranged to be actuated by said section in a predetermined positionthereof whereby to break the motor circuit.

16. The combination with a chair base having a reciprocally mountedchair raising section thereon and a reversible electric motor foroperating said section, ofa switch comprising a pair oi fluid contactunits interposed in the circuit connections of the motor for cooperationv in difierent predetermined positions to complete the circuit, amovably mounted support for each of said units, manually controlledmeans for moving said supports whereby to move said switch units fromnormal circuit breaking position to said predetermined circuit closingpositions, spring means for returning said supports to normal position,means for retarding the action of the spring means to afford arelatively slow return movement of said units, and additional operatingmeans for said movably mounted supports responsive to the movement ofsaid section in a predetermined position thereof whereby to break themotor circuit.

17. The combination with a chair base having a reciprocally mountedchair raising section thereon and a reversible electric motor foroperating said section, of a pair of oscillatory supports on the basehaving intermeshing gear segments thereon, a fluid contact switch unitcarried by each support, said units being included in the motor circuitand normally held in circuit breaking position by said supports, a footpedal operatively associated with one oi said segments, spring means forreturning the pedal and segments to normal position, an operating armassociated with each of said supports, a link connected with said armsfor operating the same, and an actuating member for the link arrangedfor operation by the chair section upon failure to release the pedalwhen the section is moved to a predetermined position whereby the switchunits are moved to circuit breaking position.

18. The combination with a base having a reciprocally mounted memberthereon and a reversible electric motor for operating said member, of aswitch having circuit connections with said motor, a pair of spacedpedals and an intermediate pedal mounted on the base, operating saidelement connected with the other of said I spaced pedals for operationthereby, and additional operating means under the control oi saidreciprocally mounted member for automatically operating said switch indiil'erent predetermined positions of said member to break the circuitwhereby to discontinue operation of the motor.

ADAM J. MAY.

